Machine for the calculation of reenforced concrete



Feb. 21, 1933.

w. SABATlNl 1,898,398

Filed April 2, 1929 2 Sheets-Sheet 1 Feb. 21, 1933. w $ABAT|N| 1,898,398

MACHINE FOR THE CALCULATION OF REENFORCED CONCRETE Filed April 1929 2 Sheets-Sheet 2 *75 F :cmq. 14.28 13.95 13.62 13.30 12.98 12.68

wzcmq. 22.32 21.79 21.28 20.78 20.29 19.81 .r4 z H :cm. 2s.11 24.75 24.59 24.00 23.63 23.25 I d= O.25H H 1 QM w F cmq. 11.82 11.45 11.09 10.15 10.41 10.08

F :cmq. 2.1246 1.9316 1.1518 1.seso 1.4525 1.3205

P D ,f D :Cm. 21.24 20.14 20.25 19.11 19.51 18.85 1.6 F :cmq. 8.870 8.457 8.064 7.688 7.330 was L j :cmq. I 0.425 0.405 0.385 0.367 0.350 0.335

W abcchi zi Patented Feb. 21, 1933 PATENT OFFICE WASHINGTON SABATINI, OF GENOA, ITALY MACHINE FOR THE CALCULATION OF REENFORCED CONCRETE Application filed April 2, 1929, Serial No. 351,888, and in Italy April 4, 1928.

This invention relates to a device for the calculation of reenforced concrete. This device -comprises substantially a number of concentric rotatable annular scale elements mounted within a stationary annular scale element, the said rotatable annular scale elements being adjusted by acrank arm adapted to be rocked and to be coupled with the annular elements. The said crank arm is rigidly connected to the pivot of a scale drum which indicates the result. The graduated rotatable annular elements are rotated by means of buttons carried by a crank forming a radial arm fastened upon a vertical shaft arranged in the center of the machine, which buttons are thus arranged upon this arm in correspondence with the underneath lying annular elements to enable its engagement in holes of these elements so as in rotating the arm to pull along these elements at engaged button and to leave every element immovable if the button is disengaged from the relative annular element.

The working of the device is so intended that with the rotation of the crank arm with all the buttons engaged with the respective annular elements a useful displacement will be obtained between the outer movable annular element and the stationary graduation. By disengaging the button of the outer movable annular element, this element remains immovable while in rotating the crank arm the annular element adjacent to this stationmy one with all the further annular elements inside of it will be displaced.

Circular calculating devices having a number of concentric annular scale elements which contain logarithmic graduations are already known. Calculating devices are also known wherein concentric relatively arranged rotatable circular scales are adjusted by a rocking arm adapted to be coupled.

However, in these devices, the rockable crank arm is not rigidly connected to a scale drum which directly indicates the results.

A constructional form of the device according to the invention is shown in the accompanying drawings.

59 Figure 1 is a plan.

Figure 2 is a vertical longitudinal central section.

Figure 3 is a partial outer view of the device comprising a scale with diagrams of constructional elements which is secured externally to the wall of the casing and provided along a reading slot and also compris ing a reading magnifying glass adapted to be shifted along the slot and Figure 4 shows a part of the cylinder carrying the indicia, in front of the corresponding elements of calculation.

The annular element 1 is secured to the cover of the casing and bears the lay-off data. The numbers on the said annular element indicate the total loads (own weight plus additional load) expressed in hundred kilo. The pointer mark P belonging to the said annular scale element is located on the second annular element. The remaining eight annular elements 2 to 9 are adjustable and bear the graduations (scales) for the variables, the corresponding pointer marks thereof being located on the following annular element.

The annular element- 2 contains:

(a) graduations for the span of the beams, floors and brackets, the pointer mark L of which is located at 18 on the third annular element;

(b) graduations 0f the diameters of the tanks, the pointer mark D of which is located at 19 on the third annular element;

(0) graduations of the ratio between the side of the foundation plate and side of :1 pillar, the pointer mark c/a thereof being located. at 20 on the third annular element;

((5) graduations of the ratio between length and side of a pillar, the pointer mark L/a thereof being located at 21 on the third annular element;

(a) graduations of the ratio between length and diameter of a pillar (resistance to breakage in case of round pillars) the pointer mark L/D thereof being located at 22 on the third annular element.

The annular element 3 contains:

(a) graduations of the moments of flexure, the pointer mark M thereof being located at 17 on the fourth annular element;

(b) graduations of the moments of flexure for calculating the bails, the pointer mark M thereof being located on the fourth annular element; V

(e) graduations of the percentage of the iron content in the pillars, the pointer mark F thereof being located at 23 on the fourth annular element.

The annular element l contains: 7

(a) graduations of the permissible stress in connection with floors, brackets and foundation plates, the pointer mark 0 thereof being locatedat 16 on the-fifthannular ele-: ment;

(b) graduations of the permissible stress for beams, the pointer mark 0' thereof being located at 24 on the fifth annular element;

(0) graduations of the permissible stresses of the iron for the tanks, the pointer mark 0' thereof being located at 25 on the fifth annular element;

(d) graduations of the composite permissible stresses for floors, brackets, foundation plates, beams and pillars, the pointer mark 0 thereof being located at 26 on the fifth annular element.

The annular element 5 contains:

(a) graduations ofthe moduli for floors,

tions of the thickness of the floor strip belonging to the beam (in function of H), the pointer mark (Z thereof being located at 30 on the seventh annular element.

'The annular element 7 contains p (a) graduations of the widths-of the floor strip belonging to the beam (in function V of H) the pointer mark 6 thereof being lorated at 31 on the eighth annular element;

, graduations of the widths of the strip or floor or bracket coming into consideration, the pointer mark 2 thereof being located at 32 on the eighth annular element.

The annular element 8 contains:

(a) graduations of the double armature for floors, the pointer mark X thereof being located at 33 on the nin h annular element;

(Z1) graduations of the double armatures for beams, the pointer mark Y thereof being located at 34 on the ninth annular element.

The ninth annular element bears the pointer marks for the scales of the double armature. The eight adjustable annular elements 2 to'9 are adjusted by means of eight buttons bearing corresponding marks viz. P, L, M, o, m, (Z, 6,. in the case as shown. These buttons 16 serving as clutch elements are slidably and frictionally mounted on a crank arm 10 which is secured to the vertical shaft 11. The shaft 11 is held by a bottom bearing 12 and the innermost annular element designed as a bearing, the said shaft 11 being also rigidly connected to the cylindrical indicating drum 13. The buttons 16 may be coupled and uncoupled separately with other clutch elements in the form of sockets 17 in the movable annular elements provided below the same. On the outer surface of the cylindrical drumc13 the solutions are tabulated in the direction of the height of the drum at solutions correspondent to the values of the variables which have been'fixed by arresting the eight rotatable annular elements in a certain relative position according to the actual problem, whereupon these annular ele- I ments are adjusted consecutivelyv from the exterior to the interior. 7 I

A practical numerical example tions obtained by adopting the most current formulae as specified below isishown in F igure 4, in which the first five. rows of numerical solutions are shown in regard to the corresponding elements to be calculated. As it is clear from acomparison of every two consecutive numbers of each horizontal line the progression of the values is geometrical, that is, the same .quotient is obtained by dividing each of the successive numbers by the preceding number. In view of this fact, the values as given are sufiicient for completing the whole-numerical table inscribed on the surface of the cylindrical drum.

. Figure 1 shows the device in the zero position. In this position the above mentioned pointer marks of the variables indicate the fundamental character of the calculations to be made with the machine:

'L=m 1.00; i l[=PL/10; 00 45; a ==1200; m=15;

ZJ=3H (for beams); D=m 1.00 (for tanks) V c/a=3 (for floors or foundation plates);

L/a=15 (for pillars); L/D=13 (pillar brackets) z= 100 centimeters brackets) F =0 (double armature).

(width of floors or The calculation of the valuesto be found lying annular elements, is brought in the direction of the zero line of the stationary .scale. All eight annular elements are rotated by the rotation of the crank arm until the pointer mark P (not visible in Figure 1' be cause it is covered by the button P) is oppoof soluelement.

messes site the desired load on the outer annular The button P is now uncoupled whereby the corresponding annular element becomes stationary and consequently the pointer mark P remains opposite the adjusted load value. The crank arm engaging withthe remaining seven buttons is further rotated with the seven annular elements belonging thereto until the pointer mark L of the second annular element is opposite the given length on the first movable annular element. All the remaining buttons are now gradually raised until all of the given values brought into a suitable position behind the Y reading slot 15 on one side wall of the easing whereby the dimensions can now be readily read in the reading slot 15 after adjusting the reading magnifying glass 14 in conformity with the figure representing the constructional element to be calculated which figure together with other figures is inscribed on a scale plate provided at the reading slot.

The numbers on the outer stationary annular element representing, as already stated, the total loads ofown set plus additional load, expressed in hundred kilo. If these numbers are multiplied by 1000, that is to say omitting the decimals, the numbers indicate the moments of flexure .expressed in cm/kg. If, therefore, in connection with these calculations the moments of flexure are directly lead off, the pointer mark P is brought to the desired moment, the buttons P, L, M, are released and the adjustment or setting of the further variables is continued.

If it is desired to calculate brackets by means of the moment of flexure, the pointer mark P is brought to the desired moment and the buttons P and M are released. The second movable annular element is then rotated until the marks P, L or PL/2 (according as it concerns a load to be concentrated or uniformly distributed at the end) corresponds with the pointer mark M on the third movable annular element. ton L is then released from the corresponding annular element and the adjustment or setting of the further variables is continued. As two divisions are provided on separate annular elements, one division refers to the iron and the other division to the thickness of the concrete.

When calculating the ironarmatures for foundation plates, an amount that is twice that indicated by the annular elements must be. taken. \Vhen calculating tanks the numbers of the outer annular element represent The butthe heights, calculated from the liquid level,

Calculation of a floor under the following conditions:

P=g 25; L=m 3.50; M=1/10; o'=,37990 (combined stress or tension) m=20; 2 100 centimeters (iron armature per current meter).

1. The device is brought in the zero position, the counter mark P is then rotated to 25 g and the button P is raised.

2. The counter mark L is brought to 3.5 meters and the button L is raised.

3. The button M is raised without rotating the counter mark M because M already points to the desired adjustment or setting 1/10.

4. The counter mark 0 is brought to the combined stresses or tensions 37-990 and the button is raised.

5. The counter mark m is rotated on, the graduation from h to 20 and the button m is raised.

6. The button (Z is raised.

7. The button I) is also raised without rotating the counter mark because the latter already points to 100.

8. After the machine has thus been set to the desired data, the reading glass is shifted on the scale of figures opposite to the figure for floors and h=1125 centimeters is read.

In order to find the cross section of the iron armature, all the above operations are repeated with the exception of the fifth wherein the pointer mark on must be rotated to 20 of the graduation for iron.

Then the approximate iron section F equals 9.10 square centimeter is read.

For the cross section of the bails the approximate value of w 14.20 square meters is readily found which corresponds to the section for the half of the floor.

For the purpose of illustration of the operation of the subject matter of the invention, the following example indicates how the corresponding graduations have been fixed with regard to the side of the factors and of the results.

The formula used for calculating rectangular beams is in which M is the bending moment of the section to be calculated 1) the width coming into consideration and 1, a known function of the modulus and the safety load of the concrete (a and of the iron (o that is to say The value of M for equally loaded beams may be written M=P L Xa, in which P is the equally distributed total load, L is the span and a is a factor dependent on the stress.

m, b, and selected a number of values for P, each of these valves receive a certain P, L, on, (T 07,7721, 6, 1.

[value of h. The values of P coming into consideration are contained on the first annular element and the corresponding values of h are contained in one (the first) row of numbers provided on the drum.

By varying the value of L and by maintainmg the values of a, a o m, b, the calculations for some values of P are effected and the corresponding values of h are determined. The crank is now rotated until the counter mark for P has pointed to one of the previously calculated values and the angle is measured for which the crank and the drum connected therewith must be rotated in order to bring the corresponding value of h in the line of sight of the ocular. The annular element, which bears the'pointer mark for L, is now rotated an annular amount equal to the above mentioned angle and the previously determined value of L is inscribed on the opposite (outer) annular element. It has been found that for each value of L with a con- 7 now rotated until the pointer mark indicating the load comes opposite one of the previously determined values and the angle about which the crank must be rotated is measured in order that the calculated value of h entersthe line of sight of the ocular. The pointer mark of a is now rotated through this angle and in accordance with the new pointer mark adjustment or setting the determined Value of a is then inscribed.

By repeating thisoperation for a number of values of 0c the necessary positions of some basic values for an accurate graduation are determined. 7

It is to be noted that for each value of a with a constant increase or decrease of the values of P, the angles through which the annular element must be rotated remain constant.

In like manner the remaining divisions corresponding to variables are determined. For the variables 0 o m, wherein with the same increase or decrease of the other variables, constantangular displacements are not obtainable, the average angular displacements have been inscribed with a suflicient approximation.

Having thus fully described the invention what is claimed as new and desired to be secured by Letters Patent is:

1. A device for the calculation of reinforced concrete including eight concentrical" independent annuli rotatable within an outer fixed annulus, on which the figures relating to the weights to be supported by the construction are inscribed, while the rotatable annuli carry the remaining factors that are usually laid off for the calculations of concrete construction and one arrow for each set of Values that are inscribed on the outwardly adjacent annulus, the innermost rotatable annulus being provided only with such arrows, a drum carrying a number of rows of results relating to the different calculations effected, each row aligning with a particular factor of the calculation coming into considerv} ation, a rotatable crank arm integral'with the drum carrying pivot, and means for selectively engaging and disengaging the'said crank arm with any and all of the rotatable annuli, the drum showing all zeros at its reading point when the movable annuli are all engaged to the crank arm and the arrow on the firstrotatable annulus points to the zero figure inscribed on the outer fixed annulus.

2. A device for the calculation of reinforced concrete, comprising in combination, a housing having an axial slot, a dial on one of the surfaces of the housing formedof eight concentrical annular elements rotatable independently of one another and within an outer fixed annular element, each of the annular elements carrying the usual factors to be laid off for the calculations of the construction elements of the reinforced concrete, a pointer inscribed, on each of said annular elements and pointing to the indicia of the adjacent outer annular element, clutch ele ments on the said annular elements, a crank arm above the plane of said annular elements, corresponding selectively disengageable clutch elements mounted on said crank arm into consideration for each particular case,

until the pointers thereon are brought into correspondence with the value to be set, and particular marks on the casing, adjacent to the said slot, for indicating for which element of construction the corresponding figures re late, the said annular elements being left idle after each setting so that the dial formed by the said concentrical annular elements after completion of the angular displacements shows by the relative positions of the annular elements the factors as laid ofi for the calculation effected, the result of which is directly read upon the part of the surface of revolution that appears through the slot in the casing of the device in front of the corresponding mark on the casing.

In testimony whereof I have signed my name to this specification.

WASHINGTON SABATINI. 

